What's in numbing drops that optometrists use that makes your eye numb? is it similar to lidocaine that dentists use in your mouth? i'm just curious.

Yes: Numbing eye drops contain a local anesthetic similar to lidocaine.

Simmilar : Usually a topical local anesthetic related to lidocaine, tetracaine , is used for ophthalmic anesthesia. It is more potent and longer lasting.

Proparacaine: Most eye doctors (ophthalmologists and optometrists) use proparacaine or tetracaine eye drops as a topical anesthetic to examine the eyes and measure the intraocular pressure. It is similar to other local anesthetics such as lidocaine.